1. Field of the Invention
The invention relates to a stroller and more particularly to a jogging stroller that facilitates the natural periodic arm movement of the person propelling the stroller while jogging.
2. Description of the Related Art
A conventional jogging stroller is typically configured as a carriage with three wheels that enables the user to jog while pushing the stroller. However, current designs inhibit the natural arm rhythm of a runner as she/he pushes the stroller forward, because the only way to transfer force to the stroller is through the stationary push-bar style handle. Trying to propel the stroller through the stationary bar while running becomes uncomfortable; as a result the user of the stroller resorts to methods for propelling the stroller that are not safe for the child occupant and/or tries to maintain contact with the stroller in ways not recommended by the manufacturer.
It is well known that, during running, the limbs of the human body move in a highly synchronous and rhythmic manner. (The Evolution of the Study of the Mechanics of Running: Relationship to Injury, McClay I., J Am Podiatry Med Assoc. 2000 March; 90 (3): 133-48). For example, at any given time during the act of running, the position of each arm is highly dependent on the position of the other. The same can be said for leg motion during running. Positional dependence of limbs while running is crucial to the human body's ability to locomote in a fluid, balanced and coordinated manner. All of the patents, patent publications, and non-patent literature cited in this Specification are hereby expressly incorporated by reference herein.
It is also well known that if any one of the four human limbs is prevented from its natural movement during running, then overall rhythmicity and limb coordination is not possible. Disruption of coordinated limb motion during running can result in reduced energy efficiency, deterioration of general running performance and, in some cases, an increased risk of injury to the runner.
There have been several past attempts to address this issue. For example U.S. Pat. No. 6,196,947 discloses a stroller having a pair of independent pivotally connected arms with handles for the user to grasp and a device to generate resistance to the arms' forward pivoting motion. By overcoming the force of the resistance device, be it an elastic cord, spring, piston or bellows, the user generates a reaction force on the frame of the stroller that propels it in a forward direction. Similarly, U.S. Pat. No. 5,876,309 has a pair of independent pivoting arms also attached to resistance devices, in this case shock absorbers, and is propelled in a similar manner. U.S. Pat. No. 6,722,689 also operates with a resistance device. In this patent a coil spring is used on each arm's handle. Another device, U.S. Pat. No. 5,674,165 has independent pivotally connected arms and a friction resistance device on each arm. This device requires the user to overcome the resistance on both the forward and backward stroke of the arm and has no means for establishing an inter-dependent motion relationship between the jogger's arms. The arm paths of these prior art devices are better than the stationary bar for addressing the problem of jogging arm motion, but these devices do not address the inter-dependent motion relationship between the jogger's arms during the act of pushing the stroller. Each arm's movement is independent of the other, which means balancing the force between the jogger's arms to propel the stroller and coordinating the arms' movement relative to one another is not facilitated in these devices. Such resistance devices cause the user's input energy to surge from one arm to the other.
As noted above, there are a number of strollers available designed to be pushed by a jogger. However, none of these devices address the positional dependence in relation to the movement of the jogger's arms during the act of pushing the stroller. As a result the jogger is required to input a force for each arm that surges from the total force necessary to push the stroller to zero. There is, therefore, a need for a jogging stroller that can accommodate the user's natural and synchronous arm motion while simultaneously distributing between both of the jogger's arms the force required to propel the stroller.